From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Subject: Re: [PATCH 2/2] ARM: tegra: Add high speed UARTs to Jetson TK1 device tree Date: Tue, 19 Jan 2016 09:32:46 -0700 Message-ID: <569E652E.5020907@wwwdotorg.org> References: <1453209155-6213-1-git-send-email-ralf@ramses-pyramidenbau.de> <1453209155-6213-3-git-send-email-ralf@ramses-pyramidenbau.de> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1453209155-6213-3-git-send-email-ralf-ex4EvEgDZR1o7HI0AxOeTKwczVv4G7md@public.gmane.org> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Ralf Ramsauer Cc: linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-tegra@vger.kernel.org On 01/19/2016 06:12 AM, Ralf Ramsauer wrote: > This patch enables the APB DMA high speed UARTs of the Jetson TK1. In the cover letter, you mentioned that these ports are exposed on the expansion connector. It'd be useful to mention that fact here too, since the cover letter doesn't make it into the git commit log. However, given that, I don't think we should apply this patch. We can't know ahead of time what hardware is connected to the expansion header; the pins aren't dedicated to be serial ports (they could be GPIOs and probably other functions too depending on the pinmux settings), and different people will connect different hardware or none at all. Hence, the default DT should not enable IO controllers for the pins on the expansion connector. The best approach these days is to use DT overlays. You may need to add some "hooks" into the Tegra base DT files to allow overlays to be used; they weren't written with overlays in mind.